For watching TV programs on a computer display, a signal processing interface such as a TV box or a TV tuner card is coupled to the computer system for receiving and converting cable-transmitted or broadcast TV signals into a format suitable to be displayed by the computer system.
With the improvement of mobile computing technologies, portable electronic devices with advanced mobile computing functions are created and developed. Examples include laptop computers, personal digital assistants (PDA), small-size liquid crystal displays (LCD), and so on. These electronic devices play more and more important roles in our daily lives because they provide a variety of utilities to people and change our ways of lives. Taking the application of a computer to TV program watching as an example, it is very convenient for people outdoors to watch wirelessly transmitted TV programs as long as a notebook computer with a built-in or plugged-in TV tuner card is available. Generally, the TV tuner card receives TV signals transmitted in a radio-frequency (RF) form via an antenna, and then converts the TV signals into a format suitable to be displayed by the computer.
Please refer to FIG. 1A, which schematically shows a notebook computer 10 equipped with a TV tuner card 12. The TV tuner card 12 is typically a cardbus-type or ExpressCard-type interface card. It can also be a TV interface card with USB expanded functions. The TV tuner card 12 is combined with the notebook computer 10 by way of a transmission interface 11, and provides the expanded function for the notebook computer 10. As shown in the figure, the TV tuner card 12 is mounted to the transmission interface 11, and is further coupled to an antenna 13 for receiving therefrom the TV signals.
Since the antenna 13 is for use with the TV tuner card 12, it is preferable that the antenna 13 is disposed near the notebook computer 10 carrying the TV tuner card 12. Furthermore, the antenna 13 is generally extensible and retractable by being exerted with a pulling or pressing force on the tip 131 thereof. In addition to the length, the angle of the antenna 13 is generally adjustable in order to receive TV signals with a better quality. However, the elongated and/or tilted antenna 13 is subject to fall due to lost center of gravity. The situation becomes worse when the object supporting the notebook computer 10 as well as the antenna is shaky.
For solving the unstable problem of the antenna 13, a securing base 130 having a relatively large area can be mounted under the antenna 13, as illustrated in FIG. 1B. Conventionally, the antenna 13 is fixed onto the securing base 130 by way of a magnetic force, but the securing base 130 is just placed on a plane of the supporting object without any connection. Then, when it is necessary to pull or pivot the antenna 13 for adjusting signal intensity, as shown in FIG. 1C, the securing base 130 is likely not stable enough for easy operation with one hand. On the other hand, if the securing base 130 is fixed onto the supporting object to improve stability, the mobility of the antenna 13 together with the notebook computer 10 will be adversely affected.